News

Society of Biology responds to latest GM food study

20th Sep 2012

The Society of Biology and a number of its learned Fellows have cautioned that the conclusions drawn from a report released this week, claiming long-term health effects from Monsanto’s Roundup herbicide and from a type of genetically modified (GM) Roundup-resistant maize, need to be considered in context. The paper published in Food and Chemical Toxicology claims that in lifetime feeding studies, rats fed on a diet containing NK603 Roundup-tolerant GM maize, or given water containing Roundup, died earlier than rats fed on a standard diet - suffering mammary tumours and severe liver and kidney damage.

The authors of the paper have been criticised for overstating their conclusions and not providing sufficient statistical backing or experimental information. Comparisons were made between ‘treated’ groups and ‘untreated control’ groups, which each comprised only 10 rats of a particular sex, making it difficult to draw conclusions. The strain of rat used in the study is also known to be susceptible to tumours.

Dr Mark Downs, Chief Executive of the Society of Biology, commented:

“Studies to assess the safety of food for human and animal consumption are extremely important. However, it is difficult to draw any conclusions from the data in this study and the results need to be considered alongside the accumulated evidence on the safety of herbicides and GM plants.”

“Some of the effects are presented in a way that makes it difficult to evaluate their significance. For example, there does not appear to be a statistical analysis of the mammary tumours. These occur quite often in [30% of] untreated animals. One would usually also take into account the historical controls in the testing lab, in reaching a conclusion. The pesticide itself has been subject to long term studies in rodents by others.”

Prof Mark Tester FSB, Research Professor, Australian Centre for Plant Functional Genomics, University of Adelaide:

“The first thing that leaps to my mind is why has nothing emerged from epidemiological studies in the countries where so much GM has been in the food chain for so long? If the effects are as big as purported, and if the work really is relevant to humans, why aren’t the North Americans dropping like flies? GM has been in the food chain for over a decade over there – and longevity continues to increase inexorably.

“Finally, of course, this was a study of one event with one gene. To then extrapolate to all genetically modified crops is absurd. Even if it eventuates that there is an issue with this one event, or even this one gene, there is no reason at all for other genes introduced using GM to carry the same burden of risk. GM is an adaptation of a natural process that occurs all the time all over the planet – it is ‘only’ a technology, a technique. It is how it is used that is more important. Generalisations about the risk of the technology per se are absurd.”

Prof Rob Chilcott FSB, Head of Toxicology at the University of Hertfordshire and Chair of the UK Register of Toxicologists:

“Clearly, there is on-going concern over the safety of genetically modified foods and synthetic chemicals in our diet and it is imperative that we have strong, scientific evidence to make rational, informed decisions on their suitability for public consumption. I do not think that the evidence presented in this study is sufficient to end that debate. The limited number (10) of animals in each group fell well short of that required to provide a statistically robust analysis. Furthermore, the incidence of tumours reported in the study for control and each treatment group were within the normal expected range for the strain of rat used.”

Prof Ottoline Leyser FSB, Associate Director of the Sainsbury Laboratory, University of Cambridge:

“Like most of the GM debate, this work has very little to do with GM. The authors of the paper do not suggest that the effects are caused by genetic modification. They describe effects of the Roundup herbicide itself and effects that they attribute to the activity of the enzyme introduced into the Roundup resistant maize. There is good evidence that introducing genes in to crops using GM techniques results in fewer changes to the crops than introducing them using conventional breeding.

“This is unfortunately rather a subtle point and is somewhat tangential to the immediate issue.”

Reference

Séralini et al. Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modiﬁed maize. Food and Chemical Toxicology 2012